Method of manufacturing polyethylene



United States Patent 3,513,150 METHOD OF MANUFACTURING POLYETHYLENE Ryo Matsuura, Shigeo Kamimura, Koichiro Iwasaki, Kazuo Yamaguchi and Jihei Inomata, Tokyo, Japan, assignors to Mitsubishi Chemical Industries Limited, Tokyo, Japan, a corporation of Japan No Drawing. Filed Nov. 23, 1965, Ser. No. 509,425 Int. Cl. C08f 1/66, 1/72 U.S. Cl. 26094.9 11 Claims ABSTRACT OF THE DISCLOSURE Polyethylene of relatively low molecular weight is produced in a hydrocarbon solvent in the presence of (1) 'y-alumina having a particle size of to 100 microns and reacted with gaseous titanium tetrachloride at 200 to 700 C. in a fluidized state and which may be optionally chlorinated, (2) a cocatalyst selected from the class consisting of a metal of Groups I, II and III of the Periodic Table, a hydride and a complex hydride of said metal and (3) hydrogen.

This invention relates to a method of manufacturing polyethylene, more particularly to the improvements in the catalytic polymerization of ethylene at relatively low temperatures and under relatively low pressures.

It has been known that u-olefins such as ethylene may be polymerized using certain catalysts, which are produced by heating a mixture of alumina and a halide of a transition metal of the Group IV, V or VI of the Periodic Table. In accordance with such method polyethylene may be obtained at relatively low temperatures, i.e. up to about 350 C. and under relatively low pressures, i.e. up to about 350 kg./cm. G. However, the polymers obtained by such method cannot meet the requirements for the production of various moldings invaluable from practical view point.

The first object of the invention resides in the improvements in or relating to the above-mentioned method for polymerizing ethylene. Namely, the invention provides such polyethylenes that is highly suitable for the production of moldings invaluable from practical view point which include injection moldings such as crates and containers, extrusion moldings such as films, sheets and filaments and blow moldings such as bottles. In other words, the first object of the invention resides in the provision of a method for the production of some kinds of polyethylene having an appropriate certain molecular Weight, molecular weight distribution, and crystallinity to meet requirements in the respective uses.

The second object of the invention resides in the provision of polymerization catalysts particularly fit for the production of polyethylene to accomplish the abovementioned objects.

The first object is accomplished by the method of polymerizing ethylene in an inert hydrocarbon solvent at a temperature of up to 350 C. under a pressure of up to 200 kg./cm. G. in the presence of a catalyst selected from the class consisting of a reaction product of 'y-alumina with titanium tetrachloride and a chlorination product of said reaction product, and a cocatalyst selected from the class consisting of a metal of the Groups I, II and III of the Periodic Table, a hydride and a complex hydride of said metal which method is is characterized in presenting hydrogen in said polymerization to improve the properties of polyethylene produced.

The second object of the invention is accomplished by reacting particles of 'y-alumina with gaseous titanium tetrachloride diluted by an inert gas at an elevated temperature in a specific range in a fluidized state, or by fur- 3,513,150 Patented May 19, 1970 ther causing the reaction product thus obtained to come in contact with a chlorinating agent.

Other objects of the invention and the mode in which the objects are accomplished will be apparent from the following description.

'y-ALUMINA In accordance with the invention 'y-alumina is used to produce polymerization catalyst.

'y-alumina may be obtained by calcining a known crystalline alumina hydrate such as for example Hydrargillite (Gibbsite), Bayerite, or Boehmite under specific conditions. Generally, the calcination of said crystalline alumina hydrates results in various crystallographic transitions, i.e., intermediates such as y 7 6-, K-, and fi-alumina, dependently of the calcining temperature and the kind of starting alumina hydrates which intermediates eventually turn out tit-alumina. The abovementioned intermediates will be referred to hereinafter as y-alumina. 'y-alumina has a crystalline structure in which a specific position is occupied by hydrogen atom regularly or irregularly, showing a clear X-ray diffraction pattern at a 1.39-1.40 A. position.

'y-alumina which is applicable to the production of catalyst of the invention is advantageously manufactured by calcining the aforementioned known crystalline alumina hydrates of particle size, especially in the range from 10 to 100 microns at a temperature from 300 to 700 C., preferably from 400 to 600 C. in a water-free inert gas such as nitrogen or air.

PREPARATION OF CATALYST Three methods may be applied to the production of polymerization catalyst for use in the invention as follows:

(1) The first method comprises passing gaseous TiCl diluted by a dry inert gas such as N or air through a vertical type reactor filled with the abovementioned 'yalumina of 10-100 micron size upwardly from the bottom at a temperature from about 200 to 700 C. preferably from 300 to 500 C. at a linear velocity so as to maintain an appropriate fluidized state in order to effect the reaction of -aIumina and TiCl The dilution of TiCL, by use of an inert gas is carried out by mixing beforehand the vapor of TiCl. maintained at a boiling temperature with an inert gas such as nitrogen, or by saturating the inert gas with TiCl. at a temperature from 10 to 100 C., preferably from 30 to C., or by introducing separately the vapor of TiCL, and the inert gas into the lower portion of the aforesaid reactor.

The flow rate of gases (TiCL, and N passing through the reactor is a factor of supreme importance to carry out the reaction of -alumina and TiCl The flow rate of the gases at the inlet of said reactor for maintaining 'alumina in a fluidized state corresponds to a linear velocity in the range from 10 to 2000 cm./min., preferably from to 700 cm./ min. TiCl in an amount in the range from about 0.01 ml. to 10 ml. per 1 gram of -alumina is required for the reaction.

The chemical structure of the reaction product obtained by the abovementioned method has not become known to us as yet. However, we are certain that the reaction product is neither a mixture of 'y-alumina and TiCl. nor y-alumina having TiCl, adsorbed. For example, should the reaction product merely a mixture of TiCL, and 'yalumina, almost all the amount of TiCL, ought to be extracted by adding a solvent such as cyclohexane to the reaction product. In practice, however, an addition of cyclohexane to the reaction product followed by heating resulted in substantially no extraction of titanium compound. Further, should the reaction product be -alumina having TiCl adsorbed, a nitrogen treatment of the product ought to result in separation of TiCl showing reduced Tiand Cl contents. In practice, however, when subjected to a nitrogen gas treatment the reaction product indicated no appreciable change in the Tiand Cl contents.

(2) The second method for producing catalyst of the invention comprises causing the reaction product obtained by the abovementioned first method to come in contact in a fluidized state with a gaseous chlorinating agent diluted by a dry inert gas such as nitrogen or air at a temperature of 100 to 600 C., preferably of 200 to 500 C. by introducing said chlorinating agent to the reactor from the bottom thereof at a linear velocity in the range from to 2000 cm. per minute, preferably from 100 to 700 cm. per minute. The chlorinating agents include chlorine, hydrogen chloride, thionyl chloride, silicon tetrachloride, and nitrosyl chloride, whilst polyhalogeno hydrocarbons such as carbon tetrachloride, chloroform, methylene dichloride, and tetrachloro ethane are most preferred.

Although the chemical structure of the resulted chlorinating product has not been made clear as yet, there was noticed an appreciable increase in the chlorine content of the product.

(3) The third method for producing the catalysts of the invention comprises the first step of passing gaseous TiCl, diluted by a dry inert gas, i.e. N gas or air through a vertical type reactor filled with 'y-alumina having particle size in the range from 10 to 100 microns upwardly from the bottom of the reactor at a temperature below 400 C., preferably from to 200 C. and at a velocity fit for maintaining a fluidized state for effecting reaction of 'y-alumina and TiCl and the second step of passing only an inert gas such as N or air through the reactor at a temperature from 300 to 700 C., preferably from 300 to 500 C. However, it is to be noted that the temperature in the second step must be maintained higher than that in the first step. The flow rate of the gas or gases at the inlet of the reactor either in the first step or the second step corresponds to a linear velocity within the range 10-2000 cm./min., preferably 100-700 cm./min. The amount of TiCL; required for the first step ranges from 0.01 ml. to 10 ml. per 1 g. 'y-alumina.

The inherent catalytic activities of the catalysts produced by the abovementioned three methods differ one another, dependently of the conditions under which the catalyst was produced. For example, the catalysts having a Cl/Ti molar ratio from 2.0 to 2.4 produced by the aforementioned method (1) are suitable for the manufacture of polyethylene to be used for conventional injection or extrusion moldings. Further, the catalysts having a Cl/Ti ratio from 2.4 to 3.5 produced by the aforementioned method (2) are suitable for the manufacture of polyethylene to be used for blow moldings. Still further, the catalysts having a Cl/Ti ratio from 1.8 to 2.0 produced by the aforementioned method (3) are suitable for the manufacture of polyethylene to be used for such injection moldings as crate or container which require excellent mechanical properties.

POLYMERIZATION The polymerization of polyethylene in accordance with the invention is carried out in an inert hydrocarbon solvent at relatively low temperatures and under relatively low pressures in the presence of the aforesaid catalyst and a certain co-catalyst.

The suitable solvents include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as heptane, hexane and actane; and cycloali phatic hydrocarbons such as cyclohexane, cycloheptane and decalin.

The quantity of the catalyst employed in the polymerization determines to some extent the quantity of polymer produced. Generally, the quantity of catalyst is selected among the range 0.1-100 g., preferably 0.5l0.0 g. per 1 litre of solvent employed in the polymerization.

The co-catalysts employed in the polymerization by the method include metals of the Groups I, II, and III of the Periodic Table, a hydride, and a complex hydride of said metals. Sodium, potassium, lithium, magnesium, calcium, aluminium, sodium hydride, potassium hydride, lithium hydride, magnesium hydride, calcium hydride, lithium aluminium hydride, and sodium aluminium hydride are representative co-catalysts. These co-catalysts serve to facilitate the polymerization reaction and regulate the molecular weight of produced polyethylene; It is preferred to employ the co-catalyst having particle size of about 10 to 200 micron, dispersed in a polymerization solvent. The quantity of co-catalyst required for the polymerization varies in the range from 0.01 to 10 parts, preferably from 0.05 to 1.0 part per 1 part of the catalyst employed by weight.

The polymerization reaction takes place at a temperature up to 350 C., preferably between C. and 300 C., and under a pressure up to 200 kg./cm. preferably between 10 kg./cm. and 100 kg./cm.

The method of the invention is particularly characterized in presenting hydrogen in the polymerization reaction to suitably regulate the properties of polyethylene produced. In accordance with the invention, hydrogen free from oxygen and water is introduced to the polymerization reaction zone under a specific partial pressure so as to suitably regulate the molecular weight of produced polyethylene. The hydrogen is fed to the reactor either solely or together with ethylene in a continuous manner, or otherwise the total quantity of hydrogen is fed to the reactor at the initial period of reaction in batchwise manner. Generally, the higher the partial pressure of hydrogen in the polymerization reaction zone, that is, the greater the amount of hydrogen introduced, the lower will be the molecular weight of polyethylene produced. The partial pressure of hydrogen in the polymerization zone, that is, the amount of hydrogen introduced may suitably be selected in view of the use of polyethylene produced, kind of catalyst employed, and conditions under which polymerization reaction takes place. For example, in the case of the production of a polyethylene which is fit for the manufacture of injection moldings such as crate and container employing a catalyst produced by the aforesaid catalyst manufacturing method (3), it is required to maintain the partial pressure of hydrogen relatively high in the polymerization reaction zone. Further, in the case of the production of polyethylene, which is fit for the manufacture of extrusion moldings such as films and sheets employing a catalyst manufactured by the aforesaid catalyst manufacturing method (1), it is required to maintain a moderate partial pressure of hydrogen in the polymerization reaction zone. Still further, in the case of the production of polyethylene, which is fit for the manufacture of blow moldings such as bottles employing a catalyst manufactured by the aforesaid catalyst manufacturing method (2), it may be well to maintain a relatively low partial pressure of hydrogen in the said reaction zone. Ordinarily, the partial pressure of hydrogen in the polymerization reaction zone is selected among the range from about to /2 of the partial pressure of ethylene, the practical partial pressure of hydrogen being below 10 kg./cm.

Upon completion of the polymerization reaction, unreacted ethylene is flashed off from the reaction mixture, then catalyst and co-catalyst are separated by filtration and the resultant polymer solution is cooled to precipitate polyethylene.

In accordance with the method of the invention a polyethylene of a straight chain structure having substantially no side chains and unsaturated bonds is obtained. Further, in accordance with the method of the invention, a polyethylene of higher density having a certain molecular weight in the range 30,000-200,000, especially 40,000- 120,000 and a suitable molecular weight distribution is obtained. The said molecular weight, molecular weight distribution and crystallinity may be regulated as desired by selecting and combining the polymerization catalysts, polymerization reaction conditions, and amount of hydrogen introduced to the polymerization reaction zone.

The introduction of hydrogen to the polymerization reaction zone in accordance with the method of the invenintroduced thereto while keeping the temperature of 235 C. and the pressure at 45 kg./cm. G for effecting reaction for 2 hours. Upon completion of the reaction, the unreacted gases were flashed off from the reaction mixture which was filtered to remove insoluble matter, and

tion renders it possible to suitably regulate the molecular 5 the remaining polymer solution was cooled to 60 C. to weight of polymer produced and to improve the density take out precipitate of polymer which was washed by of polymer produced as will be illustrated by reference to about l. of cyclohexane and dried to obtain 450 g. of Examples 5 to 6 in the later part of the specification so white polyethylene. The polymer thus obtained was found as to enhance the mechanical strength of polymer pro- 10 to have 100 ppm. ash content, 0.967 density in accordduced while reducing the coloring degree of polymer proance with ASTM D-1248, 7.0 Melt Index in accordance duced. with ASTM D-1238, and 4.8 10 average molecular Thus, the present invention provides the methods of weight calculated from Tungs equation. This polymer manufacturing various types of polyethylene having reproved excellent in rigidity, showing 12.0)(10 kg./cm. spectively suitable grades for manufacturing injection of elasticity in accordance with ASTM D638, 260 moldings, extrusion moldings and blow moldings. kg./cm. of the first yield strength and 146 kg./cm. of The present invention will now be illustrated by refertensile impact in accordance with ASTM Dl822 L-shape. ence to the following examples describing representative The employment of n-heptane, toluene, or benzene in methods for the manufacture of the catalysts and the the same amount of cyclohexane gave similar results. polymerlzation of ethylene therewlth. EXAMPLE 2 EXMPLE 1 Preparation of catalyst Preparation of catalyst 130 g. commercial crystalline alumina trihydrates (Hy- 225 g. sodium hydroxide were dissolved in 525 ml. drargillite) having average particle size of 60 micron were water to which were added 95 g. aluminium chips and fed to a reactor of vertical type having mm. diameter heated to dissolve aluminium. To the solution were added and 1 m. length and calcined by passing through dry a quantity of water until the specific gravity of the filtrate nitrogen at 500 C. for 2 hours to produce 'y-alumina. reached 1.250 to obtain an aqueous solution of sodium Then, dry nitrogen saturated with TiCl at 63 C. was aluminate (Na O/Al O =l.6). To 1.25 litre of this solupassed through the reactor upwardly from the bottom for tion was introduced, while stirring, CO gas at the rate of 30 2 hours at 375 C. The linear velocity of the gas at the 1 l./min. to obtain a precipitate of crystalline alumina triinlet was kept at 140 cm./ min. to form a fluidized state hydrates (Bayerite), which was washed by water at of 'y-alurnina particles. The feed of TiCL; for the reaction C. and dried for 2 hours at 120 C. amounted to 54 ml. in total. Upon completion of the re- 130 g. of thus obtained Bayerite having mean particle y action, the reactor was purged of unreacted TiCl by passsize of 50 micron were charged into a reactor of vertical ing dry nitrogen through the reactor at 375 C. and 140 type having 30 mm. diameter and 1 m. length, and calcm./min. linear velocity for 10 minutes. cined by passing dry nitrogen through the reactor at 500 C. for 2 hours to produce y-alumina. Then, the reactor Polymenzatlon was kept at 120 C. and dry nitrogen saturated with TiCL, 40 A 1 litre autoclave was fed with 1 g. catalyst which at 63 C. was allowed to pass through the reactor upward- Was Obtained y the aforesaid method, Sodium yly from the bottom for 4 hours. The linear velocity of the ride and 400 m1. cy l h xane which was dehydrated gas at a gas inlet disposed at the lower end of the reactor before hand. The autoclave was purged of air by passing was maintained at 140 cm./min. so as to form a fluidized y nitrogen through The autoclave Was then heated state of 'y-alumina particles. The feed of TiCl for the reunder Stirring, ethylene and hydrogen were introduced action amounted to 216 ml. in total. Upon completion of While keeping the temperature at and the total the reaction, dry nitrogen was passed through the reactor Pressure at 40 kg-l'ehfhz G to effect POIYIIIeTiZatiOII Teacfor 10 minutes at a linear velocity of 140 cm./min. in ortiOh- P cohhpletioh of the reaction, the autoclave Was der to purge the reactor of unreacted TiCl The temperpurged of unreacted g s y Was filtered, the l r ature was then raised to 5 Q at hi h temperature F0 was cooled, and the preclpltate of produced polymer was only dry nitrogen was further admitted to the reactor via 0 taken out and dried. The following Table 1 shows the the bottom at a linear velocity of 70 cm./min. polymerization conditions and results thereof.

TABLE 1 Average partial Polymer- Average Polymer H2 feed, pressure ization rate of vol. of H2, time, polymer- Yield, Molecular percent kg./cm. min. ization g. weight Density 1.13 0.49 32.4 29.7 8.5Xl0 .958 2.26 1.02 82 23.5 32.1 6.9X104 .959 2.67 1. 56 104 19.3 33.4 6.3)(10 .961 4. 88 1.72 82 22.4 30.6 5.5 10 .962 8.00 3.63 75 23.4 29.2 5.0x10 .963 o 0 42 39.9 27.3 11.8X10 .954

1 Determined by means of gas chromatography. 4 2 Produced polymer (g.)lcata1yst (g). polymer1zat1on tlme 111 hour.

Polymerization 9.5 l. of cyclohexane were fed to a 25 l. autoclave and then nitrogen was introduced to purge the autoclave of air. A dispersion prepared by suspending in 0.5 l. cyclohexane 20 g. catalyst obtained by the aforementioned method and 6 g. sodium hydride was fed to the autoclave, heated under stirring, a gaseous mixture of ethylene and EXAMPLE 3 hydrogen containing 10% by volume of hydrogen was tered, and filtrate was cooled to take out precipitate of produced polymer which was dried. The results are shown in the following Table 2.

properties and whiteness. 1

TABLE 2 Average partial Average Polymer Total H2 iced pressure Temperrate of pressure, vol. of H2, ature, Tune, polymer- Molecular kg./cm. G percent kg./cm 2 0. mm ization Yield g. weight Density 47 3.8 1.66 245 67 24. 4 27 5. 4x1 4 m0 47 4. 6 2. 30 245 100 20. 2 37 3. 7 X10 965 47 0 0 245 50 37. 2 31 10. 0X10* 955 51 1. 3 0.30 255 55 28. O 25.2 6. 8X10 958 51 3. 3 1.00 255 28. 0 30. 0 4. 9x10 963 51 0 0 255 57 26. 5 25. 2 10. 6X10 954 The results shown in Table 2 suggest that if a polym- EXAM LE 6 erization reaction temperature is relatively high, the molecular weight of polymer produced is effectively lowered by the introduction of a relatively small amount of hydrogen.

EXAMPLE 4 Polymerization of ethylene was carried out in the same way as in Example 4, employing catalyst prepared by the same method of Example 4 and the same co-catalyst as in Example 4. Table 5 compares two kinds of polymers in 2 Preparation f catalyst regard to the properties which differ dependently of the presence of hydrogen in the polymerization reaction. 7 130 g. of commercial crystalline alumina trihydrates (Hydrargillite) having average particle size of micron were fed to a reactor of vertical type having 3i) mm. 2? ABLE 5 diameter and 1 m. length for calcining by dry nitrogen passed through at 400 C. for 2 hours. Gaseous TiCl d1- (1) (2) luted by nitrogen was passed at 350 C. through the reac- Polymerization conditions: tor by the same method as in the catalyst manufacturing ggi zl g flg ryst, wt. percent 0% 0.2 method of Example 2. Then, nitrogen saturated with 30 Hzfegmvolbercdfl: 5 carbon tetrachloride (chlorinating agent) at 20 C. was ifi g nrgg ls gtfii 0 L4 passed through the reactor for 2 hours upwardly from yftraggmolecula'rweightxw. M 56 o i e in ex 4.8 3.9 the bottom at 350 C. to prepare catalyst. g l t Eng T 0.223 0.9%

I 011 1 0 S ren cm Polymerizatlon 3r i modgulusyiglfimlfxlw 2 5'4 23 5 1 g. catalyst prepared as mentioned above, 0.2 g. metalfiggg g ggggggg g gg e-( 3g li sodium powder, and 400 ml. cyclohexane were fed Whiteness,Wpercent, Hunter's method 87 90 to a 1 litre autoclave. The autoclave was heated under stirring, and ethylene and hydrogen were introduced thereto while maintaining the temperature at 225 C. and the 40 total pressure at 40 kg./cm. G. EXAMPLE 7 Upon completion of the reaction, the autoclave was purged of unreacted gases, catalyst was filtered, filtrate Preparation of catalyst was cooled, and precipitate of produced polymer was I taken out for drying. The results are shown in the followg. of commercial crystalline alumina trihydrates i T bl 3, (Hydrargillite) having mean particle size of 60 microns TABLE 3 Average Polymer Hg feed rate of vol Time, polymer- Molecular percent min. ization Yield g. Density weight 1 0.8 163 11.1 30. 2 0. 959 6.1)(10 1. 5 104 14. 9 25. 9 0.961 5. 3x10 0 119 15.1 29. 9 0.956 a. 1x10 EXAMPLE 5 55 were subjected to calcination to form 'y-alumina in a verti- Polymerization of ethylene was carried out by the same method as in Example 2, employing the catalyst produced by the method of Example 2 and the same co-catalyst as in Example 2.

As shown in the following Table 4 polymers were found to have difierent properties one another, dependently of whether or not hydrogen was introduced to the polymerization reaction.

TABLE 4 cal type reactor having 30 mm. diameter and 1 in. length. The calcination was carried out by passing dry nitrogen through the reactor for 2 hours at 500 C. The reactor was further passed through, while being maintained at 120 C., by gaseous TiCl and dry nitrogen at a linear velocity of cm./min. upwardly from the bottom for 4 hours. The temperature was raised to 500 C. and at this temperature only dry nitrogen was further admitted to the reactor via the bottom at a linear velocity 70 cm./min.

Polymerization l g. of catalyst thus produced, 0.4 g. of sodium hydride and 400 ml. of cyclohexane were put into a 1 litre autoclave, which was then heated under stirring, and ethylene and hydrogen were introduced thereto, while maintaining the temperature at 235 C. and the total pressure at 43 kg./cm. 6., respectively, to carry out polymerization reaction. Upon completion of the reaction, the autoclave was purged of unreacted gases, the catalyst was filtered, the filtrate was cooled, and the precipitated polymer was taken out and dried. The results are shown in the following the temperature at 2.25 C. and the total pressure at 40 Table 6. kg./cm. G to carry out polymerization.

TABLE 6 Average Polymer partial H3 feed, pressure Average vol. of H2, .Time, molecular percent kg./em. min. Yield, g. weight Density 10.8 3. 4 180 26.8 5. 6X10 0. 965 13.0 4. 3 180 21. 4. 7x10 0. 968 0 0 60 30. 0 25 1o 0. 948

EXAMPLE 8 15 Upon completion of the reaction, the autoclave was 3 of catalyst produced by the method of Example 2, purged of the gases, the catalyst was filtered, and the an amount of sodium hydride, and 400 ml. of cyclohexane filtrate Was cooled to take out the Preclpltate of P y were put into a 1 litre autoclave, which was heated under which was dried. The results are shown in Table 8.

TABLE 8 Average Polymer partial H2 feed, pressure Average vol. of Hz, Time molecular percent kg/emfl min. Yield, g. weight Density stirring. Ethylene, and hydrogen were introduced to the EXAMPLE l1 autoclave at 225 'C. under 40 kg./om. G of total p'ressure to carry out polymerization of the reaction. 200 g. of commerclal crystalline alumlna trihydrates Upon completionof the reaction, the autoclave was (Hydrargillite) and 1 litre of water were put into a 2 purged of unreacted gases, the catalyst was filtered, the 35 litre autoclave which was heated at 190 C. for 5 hours. filtrate was cooled, and the precipitated polymer was The autoclave was then cooled, and solid materials were taken out and dried. Theresults are shown in Table 7, filtered, washed by water and dried at 120 C. for

TABLE7 Average 7 Average Polymer partial polymerpressure ization Average H feed, of Hz, Time, rate 1 molecular NaH, g. vol. kg/0111. min. Yield, g. welght percent 0.9 3.9, 1.72v 30 23.1 34.8 s.4 0.6 4.4 1.64 41 15.9 32.7 s.s 10 0. 3 2. 7 0. 96 40 14. 5 39. 0 9. 7 10 0.15 2 9 1.12 93 6. 5 30.3 8. 6x10 0.075.. 3 1 y 1.34 150 2.4 18.0 9.7 10

Produeed polymer (g.)/eatalyst (g.) po1ymerization time in hr.

EXAMPLE 9 2 hours to obtain crystalline alumina monohydrate (Boehmite) having mean particle size of 60 micron. 100 g. of Boehmite thus obtained were subjected to calcination at 550 C. to form -alumina in the same way as in Example 2 which was caused to react with TiCl in the same way as in Example .2 to manufacture catalyst.

1 g. of catalyst thus obtained, 0.4 g. of sodium hydride and 400 ml. of cyclohexane were put into a 1 litre autoclave, which was heated at 225 C. to reach the pressure of l g./cm. G. Then, hydrogen was introduced to the autoclave, and further, ethylene was introduced thereto to obtain the total pressure of 40 kg/cm. G. Polymerization reaction was carried out for 240 minutes while introducing ethylene so as to maintain said total pressure.

Upon completion of the reaction, the autoclave was purged of unreacted gases, the catalyst was filtered, and

400 ml. of cyclohexane and 0.3 g. of sodium hydride were put into a 1 litre autoclave which was heated up to 180 C. under stirring, ethylene was introduced thereto at this temperature, and stirred under 10 kg./cm. G for 1 hour. The autoclave was then cooled to be purged of the ethylene. 0

3 g. of catalyst manufactured by the method of Example 2 were added to the autoclave, which was heated under stirring, and a mixture of hydrogen and ethylene which contains 2.8 vol. percent hydrogen was introduced thereto at 225 C. while maintaining the total pressure at 40 l g./cm. G to carry out polymerization for 43 minutes. Thus, 48.5 g. of polyethylene having 98x10 average molecular weight and 0.958 density were obtained.

the filtrate was cooled to take out precipitated polymer EXAMPLE 1O which was dried. Thus, 20 g. of polyethylene having 1 g. of catalyst manufactured by the method of EX- average molecular weight of 10x10 were obtained. ample 2 0.8 g. of lithium hydride dispersed in paraffin The polymer which was obtained by the same method Wax and 400 ml. of cyclohexane were put into a 1 litre as mentioned above excepting the introduction of hydroautoclave, which was heated under stirring, and ethylene gen was found to have average molecular weight of and hydrogen were introduced thereto while maintaining 35 10 11 EXAMPLE 12 1 g. of catalyst employed in Example 2, 400 ml. of cyclohexane and an amount of cocatalyst indicated in the following Table 9 were put into a 1 litre autoclave 6. A method as claimed in claim 5, wherein the co-' catalyst is present in an amount of 0.05 to 1.0 part per 1 part of the catalyst by weight.

7. A method as claimed in claim 5, wherein the catalyst is produced by passing gaseous titanium tetrachloride di-.

and heated under stirring. Ethylene and hydrogen were introduced thereto while maintaining the temperature at luted Inert gas through a reactor of vertlcal type 0 and the total pressure at 40 kg/cm; G to carry filled w1th the y-alumrna at a temperature of 300 to 500 out polymerization. Upon completion of the reaction, and f veloclty Of 100 to 700 cm./min., subsethe autoclave was purged of unreacted gases, the catquently Passlllg a gas containing a chlorinating agent alyst was filtered, and the filtrate was cooled to take out gh the reactor in the same direction as said tetrathe precipitate of polymer which was dried. The results chloride at a temperature of 200 to 500 C. and a linear are shown in Table 9. velocity of 100 to 700 cm./min.

TABLE 9 Ctr-catalyst Average Polymer partial pressure Average Amount, of H2 Time molecular Kind g; kgn/ernfi min. Yield, g weight 1 Al powder of 200 mesh. 0.3 2 240 5. 8x10 2.. Mg powder of 100 mesh 0. 3 2 240 10 5. 4X10 3.- MgH 0:100 mesh 0.9 2 60 5. 4x10 4 can? of 100 mesh 0.3 2 120 15 5.6X104 5 LlAlH4 0:200 mesh 0.1 2 60 20 5.3)(10 What we claim is: 8. A method for production of polyethylene in a polym- 1. A method for production of polyethylene in a erization zone which comprises polymerizing ethylene in polymerization zone which comprises polymerizing ethyla hydrocarbon solvent at a temperature up to 350 C. and ene in a hydrocarbon solvent at a temperature up to 350 under a pressure of up to 200 kg./cm. G in the presence C. and under a pressure of up to 200 kg./cm. G in the of a catalyst, a co-catalyst and hydrogen; said catalyst is presence of a catalyst, a co-catalyst and hydrogen; said produced by contacting 'y-alumina having a particle size catalyst is produced by reacting 'y-alumina having a partiof 10 to 100 microns with gaseous titanium tetrachloride cle size of 10 to 100 microns with gaseous titanium tetraat a first temperature below 400 C., subsequently conchloride at a temperature of 200 to 700 C., while maintacting the particles with inert gas at a temperature of taining the 'y-alumina in a fluidized state; the co-catalyst 300 to 700 C. which is higher than said first temperais selected from the class consisting of a metal of Groups ture, while maintaining the particles in a fluidized state; I, II and III of the Periodic Table, a hydride and a comthe co-catalyst is selected from the class consisting of a plex hydride of said metal, the amount of the co-catalyst metal of Groups I, II and III of the Periodic Table, a being 0.01 to 10 parts per 1 part of the catalyst by weight; hydride and a complex hydride of said metal, the amount the said hydrogen being present at a pressure of one hunof the co-catalyst being 0.01 to 10 parts per 1 part of the dredth to one-half of the total pressure of ethylene and catalyst by weight; the said hydrogen being present at a hydrogen in the polymerization zone. 40 pressure of one hundredth to one-half of the total pres- 2. A method as claimed in claim 1, wherein the catalyst sure of ethylene and hydrogen in the polymerization zone. is produced by reacting -alumina with titanium tetra- 9. A method as claimed in claim 8, wherein the catalyst chloride at a temperature of 300 to 500 C. is produced by contacting -alumina with gaseous tita- 3. A method as claimed in claim 1, wherein the conium tetrachloride at a temperature of 50 to 200 C. catalyst is present in an amount of 0.05 to 1.0 part per 10. A method as claimed in claim 8, wherein the copart of the catalyst by weight. catalyst is present in an amount of 0.05 to 1.0 part per 4. A method as claimed in claim 1, wherein the catalyst 1 part of the catalyst by weight. is produced by passing gaseous titanium tetrachloride di- 11. A method as claimed in claim 8, wherein the cataluted with inert gas through a reactor of vertical type ,lyst is produced by passing gaseous titanium tetrachloride filled with the 'y-alumina at a temperature of 300 to 500 diluted with inert gas through a reactor of vertical type C. and a linear velocity of 100 to 700 cm./min. filled with the 'y-alumina at a temperature of 50 to 200 5. A method for production of polyethylene in a C. and a linear velocity of 100 to 700 cm./min., subsepolymerization zone which comprises polymerizing ethylquently passing only inert gas through the reactor in the ene in a hydrocarbon solvent at a temperature up to 350 same direction as said tetrachloride at a temperature of C. and under a pressure of up to 200 kg./cm. G in the 300 to 700 C. and a linear velocity of 100 to 700 cm./ presence of a catalyst, a co-catalyst and hydrogen; said min. catalyst is produced by reacting -alumina having a part- References Cited icle size of 10 to 100 microns with gaseous titanium tetrachloride at a temperature of 200 to 700 C., subse- UNITED STfATES PATENTS quently contacting the resulting reaction product with a 3,007,905 11/ 1961 Balley 26 -9 9 gaseous chlorinating agent at a temperature of to 3,105,066 9/1963 MacKenZle 600 C. until the reaction product has a Cl/Ti ratio of 3,166,542 1/1965 Orlechowskl at 2.4 to 3.5, while maintaining the particles in a fluidized 3,255,167 6/1966 Thomas state; the co-catalyst is selected from the class consisting 3,324,101 6/1967 Baker et 260-949 of a metal of Groups I, II and III of the Periodic Table, 5 3,371,079 2/1968 Peters et a hydride and a complex hydride of said metal, the amount of the co-catalyst being 0.01 to 10 parts per 1 JOSEPH SCHOFER Pnmary Exammer part of the catalyst by weight; the said hydrogen being S, M LEV1N, A i t E i present at a pressure of one hundredth to one-half of the total pressure of ethylene and hydrogen in the polymeriza- 0 -U.S. Cl. X.R. tion zone. 252-441 

